ChEMS/IMRI Seminar: Grain Boundary Segregation, Vacancies and Properties in Energy Materials

Engineering Tower 652
Yuichi Ikuhara

Department of Materials Science and Engineering
School of Engineering Institute of Engineering Innovation
University of Tokyo, Japan

Abstract: Grain boundaries and interfaces in crystals have specific atomic structures due to the lattice disorder, which are the origin of various properties not generated in bulk. Local atomic structures in the GBs/interfaces are closely related to the mechanical and functional properties of materials. Furthermore, dopants and impurities are distributed around the GBs/interfaces and play important roles in determining macroscopic properties. To design new materials, it is necessary to understand the mechanisms of property-generation by precise analysis of the atomic structures and dopant distribution. With recent advances in materials synthesis processes, the microstructure of materials can now be controlled at the atomic level. Therefore, techniques to characterize the microstructure at higher resolution are demanded. Transmission electron microscopy (TEM) is one of the most useful techniques to observe the internal structures. TEM makes it possible to perform atomic structure analysis and local composition/state analysis at the nanometer scale. The nanoscale analysis has developed dramatically in recent years. For example, scanning transmission electron microscopy (STEM) with spherical aberration correction gives column-by-column information about the elements, their position and their electronic state. Our research focuses on investigating and predicting the mechanisms for generating material properties by combining experimental techniques, such as leading-edge high-resolution TEM, STEM, energy-dispersive X-ray spectroscopy (EDS) and electron energy-loss spectroscopy (EELS) and theoretical calculations.

Bio: Yuichi Ikuhara is the preeminent worldwide scholar in the area of high resolution transmission electron microscopy and properties of grain boundaries and interfaces in ceramics. He is the author of over 650 articles (with an h-index 52). Ikuhara directs the Crystal Interface Laboratory at the University of Tokyo, which focuses on understanding how mechanical and functional properties of materials are related to the structure of internal interfaces. He received his doctorate from the Department of Materials Sciences, Kyushu University. He then joined Japan Fine Ceramics Center (JFCC) in 1988 and was the microstructure characterization division manager at JFCC from 1993. In 1996, he joined University of Tokyo as an associate professor of materials sciences. He was a visiting assistant professor at Case Western Reserve University from 1991 to 1993. He has been a professor at the University of Tokyo since 2003. His many awards include Fulrath Fellow, Fellow of the American Ceramic Society, Fellow of the Japanese Ceramic Society, and a Humboldt Research Awardee. He also holds a group leader position at JFCC and WPI professor at Tohoku University concurrently.

Hosts: Xiaoqing Pan, IMRI, and Martha Mecartney, ChEMS